Re: [RFC/PATCH 0/4] CPUSET driven CPU isolation

Ingo Molnar
2008-02-28T09:09:26Z

* Paul Jackson <pj@sgi.com> wrote:

> > i've queued up your patches in sched-devel.git
>
> Before this patchset gets too far, I'd like to decide on whether to
> adapt my suggestion to call that per-cpuset flag 'cpus_system' (or
> anything else with 'cpu' in it, perhaps 'system_cpus' would be more
> idiomatic), rather than the tad too generic 'system'.

yeah. In fact i'm not at all sure this is really a "system" thing - it's
more of a "bootup" default.

once the system has booted up and the user is in a position to create
cpusets, i believe the distinction and assymetry between any bootup
cpuset and the other cpusets should vanish. The "bootup" cpuset is just
a convenience container to handle everything that the box booted up
with, and then we can shrink it (without having to enumerate every PID
and every irq and other resource explicitly) to make place for other
cpusets.

maybe it's even more idomatic to call it "set0" and just create a
/dev/cpuset/set0/ directory for it and making it an explicit cpuset -
instead of the hardcoded /dev/cpusets/system thing? Do you have any
established naming scheme for cpusets that we could follow here?

> People doing 'ls /dev/cpuset' should be able to half-way guess what
> things do, just from their name.

oh, certainly. This is at the earliest v2.6.26 material - but now it at
least looks clean conceptually, fits more nicely into cpusets instead of
being a bolted-on thing.

Ingo